You don't want to do that anyway - users will just copy the example with minor changes.
There is not much you can do about poor choice passwords - at least your system keeps rejecting the choices until they get one that passes. Just type up a standard response to complaints.
Though you can set up an email message to notify users their password is about to expire.
In general, PAM handles authentication:
Alternately, assign random passwords and advise users to write them down and keep the slip of paper in their wallets. These passwords do not expire unless you know they need to.
The trouble with password policy is that strong passwords are hard to remember. So far, best (tested) compromise has been to tell users to think of a sentence they can easily remember and use that as a wmeumonic for their passwords. eg:
oh freddled gruntbuggly thy micturations are to me as plurdled gabbleblotchets on a lurgid bee
though it is stronger if it is not a famous quotation - and it only needs to be 8 words long:
fishing is a waste of a good weekend
put this as a policy on a public server someplace.